Riveting machine



July 10, 1962 T. I MAY ET AL RIVETING- MACHINE 5 Sheets-Sheet 1 Filed Nov. 27, 1959 IIHIIIIIIIH INVENTORS Thomas. L. May

FIG. 1

Robert H. Zcnkl giom; M. @4 4.

Arrakxvsf July 10, 1962 T. MAY ET AL RIVETING MACHINE 5 Sheets-Sheet 2 Filed Nov. 2 1959 INVENTORS THOMAS L. MAY

Y ROBERT H. ZANKL Arm/ave? FIG. 6

July 10, 1962 T. 1.. MAY ET AL RIVETING MACHINE 5 Sheets-Sheet 5 Filed Nov. 27, 1959 FIG. 9

INVENTOR. Thomas L. May

y Robert H.Zc1nkl July 10, 1962 T. L. MAY ET AL 3,

RIVETING MACHINE Filed Nov. 27, 1959 .5 Sheets-Sheet 4 V' INVENTORB Thomas L. May y Robert H. Zcmkl gwu 10.6%

I ArTDRA/EY Juiy 10, 1962 T. L. MAY ET AL RIVETING MACHINE 5 Sheets-Sheet 5 Filed Nov. 27, 1959 FIG- 15 ,4 TraR/vefr United Etates Patent 3,043,168 RIVETING MACHENE Thomas Leslie May and Robert H. Zankl, Miami, Fla,

assignors, by mesne assignments, to US. Rivet Machine Corporation, Chicago, BL, a corporation of Hitnois Filed Nov. 27, 1959, Ser. No, 855,619 4 Claims. (Cl. 784-8) This invention relates to an improved riveting machine having in combination a hopper for the support of the rivets, a driver mechanism for setting the rivets, a rivet holder that initially receives and supports the rivets prior to the actuation of the driver mechanism, an anvil and an adjustable trackway for conveying the rivets from the hopper to the rivet holder, all in timed sequence' The invention contemplates a base forming column that supports the various components of this mechanism, including a novel form of hopper device that is provided with feed mechanism adapted to deposit the shank portions of the rivets into an inclined trackway that functions to deliver the rivets by gravity to the point of ejection, where they are deposited into a rivet holder and with means associated with the hopper and the trackway that functions to prevent rivets being fed to the trackway in an improper manner and to prevent the jamming of rivets in a manner whereby the rivets are compelled to enter the trackway with their shank portions disposed in the trackway.

The invention further contemplates a novel form of trackway for conducting the rivets from the hopper that is adjustable laterally in accordance with the diameter of the shank portion of the rivets and also adjustable Vertically to accommodate the trackway to rivets of varying dimensions and to form a guiding clearance for the head portions of the rivets.

The invention further contemplates a novel driver mechanism in combination with a rivet holder and with the driver being actuated to and from a driving position by a rocker arm that is pivotally supported at a point within an extension of the column to minimize any flexibility in the extension when the rocker arm is actuated to move the driver downwardly. The invention further contemplates a driver mechanism that is supported within a guide device carried upon an upper extension of the column to be reciprocated in a vertical manner under the influence of the rocker arm and with a novel form of rivet holder that has a cooperative relation with the driver and whereby the rivet holder is actuated under the influence of the driver to and from a point adjacent to the discharge end of the trackway whereby the rivet holder is disposed in a position to receive a rivet from the trackway when the driver is in an uppermost position and, when the driver moves downwardly, the rivet holder is yieldably forced downwardly to a point where the supported rivet engages a work-piece to be riveted.

The invention contemplates a novel ejector mechanism for ejecting a lowermost rivet from the trackway to the rivet holder, such mechanism being actuated under the influence of the movement of the driver and with the rivet holder being adjustable in its travel in accordance with a particular size of rivet being employed.

Novel features of construction and operation of the device will be more clearly apparent during the course of the following description, reference being had to the accompanying drawings, wherein has been illustrated a preferred form of the device and wherein like characters of reference are employed to denote like parts throughout the several figures.

In the drawings:

FIGURE 1 is a perspective view of a riveting machine constructed in accordance with the invention,

ice

FIGURE 2 is an enlarged fragmentary side elevation of the lower end of a rivet trackway embodied in the invention,

FIGURE 3 is a plan view of the structure illustrated in FIGURE 2,

FIGURE 4 is a transverse section taken on line 4-4 of FIGURE 8,

FIGURE 5 is an enlarged fragmentary sectional view taken through the upper portion of the machine, parts being shown in elevation and parts omitted, for sake of clearness,

FIGURE 6 is a horizontal section on line 6-6 of FIGURE 13,

FIGURE 7 is a transverse section taken substantially on line 77 of FIGURE 1,

FIGURE 8 is a vertical section taken substantially on line 8-8 of FIGURE 7, parts being shown in elevation,

FIGURE 9 is a horizontal section taken substantially on line 99 of FIGURE 8,

FIGURE 10 is a fragmentary vertical section through a driver mechanism and a cooperating anvil, parts being shown in elevation,

FIGURE 11 is a section taken on line 1111 of FIG- URE 10, parts being shown in elevation,

FIGURE 12. is a horizontal section illustrating an ejector mechanism,

FIGURE 13 is an enlarged fragmentary section through a guide housing and associated parts embodying a driver device and a rivet holder and illustrating the ejector mechanism that is operative under the influence of the driver,

FIGURE 14 is a fragmentary vertical section through a rivet holder and illustrating a driver in the operative engagement with a rivet supported within the holder and,

FIGURE 15 is a fragmentary side elevation of a driver head and associated coupling means between the driver and a rivet holder.

Referring specifically to the drawings, the numeral 5 designates a base column, usually of hollow cast formation that carries a foot 6 for ground support of the device. Bolted or otherwise rigidly connected to the column 5 is a casting extension 7. The casting 7 is provided with a hollow lateral extension- 8 carrying at its outer end and rigidly supported in depending manner, a guide housing 9, for a purpose to be presently described. Bolted or otherwise rigidly connected to the forward side of the column 5, is a bracket arm 10, having an outer cylindrical head portion 11 that is vertically bored and threaded to receive a threaded shank 12, constituting the body for an upper cylindrical anvil 13. The anvil is of conventional construction and the anvil and the body 12 are axially bored to receive a rivet positioning pin 14, that carries at its lower end a piston head 15, that is biased upwardly by a compression spring 16, whereby the pin is normally projected axially above the anvil 13 to engage the usual hollow shank portion 17 of a conventional rivet 18. The rivet 18 has the usual rounded head 19. A suitable lock nut 20 functions to lock the body 12 at a predetermined elevation above the head 11 whereby to accommodate the positioning of the anvil in accordance With the particular rivet being employed and in accordance with an adjustable rivet holder, to be described. Mounted upon the upper portion of the column extension 7 in any suitable manner, is a rivet holding hopper 21. The hopper 21 carries a closure cover 22. The bottom wall of the hopper is inclined at 23 and whereby the rivets 18 are fed by gravity toward a loading mechanism. The opposite side walls of the hopper 21 are slotted to receive the upper end portion of a rivet receiving and conveying trackway indicated as a whole by the numeral 24. The trackway 24 bisects the hopper in an inclined manner to receive the rivets that are to be guided plurality of rivets from the hopper to be subsequently dumped on to the top ofthe trackway 24. The plate is oscillated by "a crank arm 28 that is journaled at its lower end by a stud 29, carried by the plate 25 and its upper end is journaled at 30, upon alug carried by grooved pulley 31. The pulley 31' is journaled upon' a suitable stub shaft 32 carried by one adjacent wall of the hopper 21; The pulley 31 is relatively large in diameter and is driven from a smaller pulley 33, carried upon a shaft 34, that is suitably journaled for rotation in bearings carried by wall extensions of thehopper 21. The shaft 34 is driven by relatively large grooved pulley 35, through the medium of an endless belt 36, from a drive pulley 37, rotatable under the influence of a suitable prime mover 38. The drive connection between the pulleys 32 and 33 is in the form of an endless belt 39.

'Means are provided to prevent the jamming of rivets into the receiving end of the trackway 24, comprising a kick-off wheel 40, fast upon a shaft 41. The wheel 40 overlies the tnackway 24 and is provided with a circurn-.

ferential group of relatively sharp and transversely extending teeth 42. The wheel 40 is driven in a clockwise direct-ion or, in opposed relation to the travel of the rivets through the trackway. The wheel 40 is spaced above the trackway a distance capable ofpermitting the passage of the rivet head 19 beneath the wheel whereby to permit the free flow of rivets downwardly by gravity through the track. The shaft 41 is suitably journaled with respect to ithe'hopper and is provided with variablespeed ratio drive means, including stepped pulleys 43, driven from a group of step pulleys 44, carried upon the shaft 34. The pulleys 43 are alternately driven through the medium of an endless belt 45. The shaft 41 is extended outwardly beyond the pulleys'43 and is provided with a knurled hand wheel 46, whereby the shaft 41 may be manually rotated.

The trackway 24, see particularly FIGURE 4 embodies a pair of generally rectangular bars 47 that are normally spaced apart to provide a clearance for the shank portions '18 of the rivets. The bars 47 are adjustable toward and from each other through the medium ofan adjusting screw 48. The adjusting screws 48 are at predetermined spaced points throughout the trackway. The screws 48 are adjustable through thernedium of a knurled head 49 and a'friction spring 50 is disposed upon the screw 48 tobear against the head 49 and the side of an adjacent 'bar 47 whereby to frictionally hold the screws against 7 accidental movement. 7

a guide clearance for the head 19 of the rivets and to Means are also provided to form maintain the rivets in accurate guiding movement through the slot formed by the spacing of the bars 47. Such means embodies an upper bar 51,, that extends for the major length of the trackway and that overlies the slot formed-by the bars 47. able to accommodate the heads 19 of rivets of varying sizes. The means for adjusting the bar 51 comprises screws 52, that are threaded into one bar 47 and rotatable under the influence of a knurled head 53. A friction spring 54 is disposed between a bearing lug 55 carried by the bar 51 and the knurled head 53 whereby the screw is held in'accurate adjusted position The bar 51 'termi nates at its upper end in a circumferential slot 56 formed in the wheel 41} substantially intermediateiits-width, The

The bar 51 i vertically adjusta terminal end of the bar 51 as disposed in the slot 56 functions to prevent rivets from entering the trackway between the bars 47 and, since the wheel 40 is constantly rotating in a clockwise direction, any rivets that tend to enter the trackway in an endwise manner, will be dislodged by the wheel 40 and thrown backward into the hopper. 'The lower end of the trackway i fixedly connected to a block 57, carried by a lower extension of the guide housing 9 thus fixedly supporting the lower end of the trackway whereby a lowermost rivet is ejected in timed sequence to a rivet nest or holder, to be described.

Adapated to traverse the guide housing 9 is a vertically movable driver head 58. The head 58 has a lower semicylindrical extension 59 terminating in a cylindrical riveting punch 60. The punch 60 is provided at its'lower end with a concave recess 61, conforming generally to the rounded head 19 of the rivet. The drive head 58 is oscillated in a vertical plane by a pivotal link connection 62, connected to the outer end of a rocker arm 63. The rocker arm 63 is pivotally supported at 64 upon a bearing member 65 that is rigidly supported within the extension 18 closely adjacent to the column extension 7. The rocker arm is actuated in a vertical plane through the medium of a crank arm 66, pivotally connected at 67 and with the crank arm 66 being carried by an eccentric band 68, engaging an eccentric 69, fast upon a drive shaft 76. The shaft 70 is driven from a pulley 71, having a suitable endless'belt connection with a prime mover 72, fixed upon a bracket 73, adjustably supported upon the rear portion of the column extension 7. The shaft 70* is suitably journaled with respect. to the extension 7 and any suitable clutch mechanism may be employed between the pulley 71 and the shaft that is intermittently actuated by a foot treadle 74, such construction being conventional and well known in the art, The vertical movement of the driver head 58 is thus actuated to and from a driving position upon the actuation of the treadle 74.

Also movable in guided relation with respect to the guide housing 9 is a rivet holder, having a shank portion 75, having one flat side that has cooperative sliding engagement with a flat side 58' of the head 58. The rivet I er 75and with the grooves cooperating to form an elongated cylindrical recess. Mounted within the cylindrical recess formed by the grooves 762ml 77, are upper and lower plugs 78 and 79, that are biased apart by a coil spring 80. As will be observed in FIGURE 13, the upper plug 78 is biased to a seating engagement in to the end portion of the groove 77, while the lower plug 79 is biased to a seating engagement in the lower end of the groove 76 thus providing a lost motion connection between the head 58 and the shank 75 of the rivet holder. The rivet holder 75 at its upper end is provided with a lateral extension 81 that'contacts. an upper limit screw 82 and alower limit screw 83 that definitely limits the upward and downward movement of the rivet holder. It being understoodof course that the driver head 58 partakes of a constant movement up and down. After adjustment of the screws 82. and 83, they are fixed against movementbvset screws 84.

Connected with the lower end of'the rivet holder 75 upon opposite sides, are a pair-of flexible plates 85, riveted or otherwise connected thereto. a The plates 85 are fixedly connected at their lower ends to a pair of cooperative rivet seat forming members 86, that forma yielda-ble rivet receiving nest during the operation of the device. Each of the members .86 have their opposed walls tapered at 87, to jointly form a taper socket forthe reception of the rivet. Each of the sockets 87 are notched at their lower ends, as at 88 to receive the shank portion 18 of the rivet and with thehead 19 of the rivet being temporarily supported upon the taperside walls of each of the members 86.

Means are provided to eject a lowermost rivet from the trackway 24 at its lower end, comprising an ejector bar 89, that traverses a rectangular opening 90 formed in the block 57. The bar 89 at its outer end is provided with a lateral extension 91 that bears against a pin 92, shiftable in a bore 93 of the block 57 and biased in an outward direction by a spring 94. The bar 89 is movable in direct alignment with the rivet nest and is cut away at its forward end to form an ejector head 95 that is adapted to engage and drive the lowermost rivet into the rivet nest. In the ejecting position, the head 95 is driving the rivet toward the rivet nest, while the body of the bar 89 overrides the next adjacent rivet to maintain the group of rivets from a further downward movement until such time as the bar 89 has been retracted under the influence of the spring 94. The means for shifting the bar 84, comprises a bell crank lever 96, that is pivoted at its upper end, as at 97 to the guide housing 9 and with the lower terminal end of the lever 96 bem'ng against the outer terminal end of the bar 89. The crank 96 is biased in a direction to shift the bar 89 to a rivet ejecting position, by relatively heavy coil spring 98, hearing against the crank 96 and the end wall of a generally U-shaped bracket extension 99 carried by the lower extension of the housing 9. Means are provided to rock the arm 96 against the tension of the spring 98, that comprises a roller 100, journaled in a forked bracket 101 carried by the crank 96 and operable through a slot 102 formed in the housing extension. The roller 10% projects into the path of movement of the driver head 58 so that, when the head 58 is shifted downwardly to the riveting position, the head 58 will bear against the roller 1139, shifting the crank 96 rearwardly against the tension of the spring 98 and permitting the bar 89 to be moved rearwardly under the influence of the pin 92 and the spring 94 to permit a lowermost rivet to be disposed into the path ofmovement of the punch 60. When the head 58 is again shifted upwardly, the spring 98 forces the lever 96 forwardly moving the bar 89 forwardly to inject a lowermost rivet into the rivet nest, it therefore being seen, that the spring 98 functions to fully actuate the bar 89 to a rivet ejecting position. With the rivet disposed within the nest, the mechanism is actuated to energize the clutch mechanism for driving the shaft 70 and the eccentric 68, causing the rocker arm 63 to move the head 58 downwardly, and, as the head 58 moves downwardly, at a predetermined timing, the head 58 overrides the roller 109, moving the crank 96 rearwardly and permitting the ejector bar 89 to be retracted, permitting another rivet to move downwardly to the lowermost point in the trackway 24. A continued downward movement causes the lower plug '79 to contact the bottom of the groove 77, picking up the shank 75 of the rivet holder and moving the riveting holder and its supported rivet downwardly toward the workpiece. With the rivet holder overlying the workpiece, the head 58 continues a downward movement against the tension of the spring 80, to the point where the driver punch 60 engages the head of the rivet, forcing it downwardly through the nest and forcing the members 86 apart to force the rivet through an aperture of the workpiece and to drive the rivet into riveting engagement with the article. A reverse movement of the head 58 carries the shank 75 upwardly where the nest is again disposed in alignment with the discharge end of the chute.

The movement of the shank 75 is limited in its upper and downward movement by the screws 82 and 83.

Operation it falls downwardly to be centered by the taper walls 37. Now, with a workpiece disposed upon the anvil 13, resting upon the projecting end of the centering pin 14, the operator actuates the foot treadle 74, in turn shifting the clutch for rotating the shaft 70 for one revolution, the rotation of the shaft 70 actuates the eccentric 69 to rock the rocker arm 63 upon its pivot 64, forcing the driver head downwardly and carrying with it the shank 75 of the rivet holder. The head 58 and the shank 75 continue their downward movement until the notches 88 of the rivet holder are in axial alignment with an aperture in the workpiece to be riveted. The rivet nest, as before stated is limited in its downward movement by the lower limit screw 83, to such position where it closely overlies the workpiece to be riveted. With the rivet holder being shifted to its lowermost position, the driver head continues its downward movement, causing the punch 60 to engage the head of the rivet, forcing it downwardly through the rivet nest, such action being possible by the movement apart of the nest forming elements 86 and a continued downward movement of the punch, drives the rivet to an axial contacting engagement with the pin 14 and then continues its downward movement, to force the rivet into engagement with the anvil 13. Immediately upon the completion of the riveting action, determined by the movement of the rocker arm 63, the head 58 is then elevated carrying with it the shank 75 of the rivet holder upwardly until it contacts the upper limit screws 82, in which position the rivet nest is in direct alignment with the discharge end of the chute 24 and in the upper movement, the head releases the roller 19%), causing the bell crank lever 96 to be biased forwardly by the spring 98, actuating the ejector bar 89 to quickly eject another rivet into the nest. next adjacent rivet to prevent jamming of the mechanism. The several parts move in timed sequence, having in mind the movement of the driver head and the movement of the rivet holder together with the movement of the crank arm 96 to a release position with respect to he ejecor bar 89 as the driver head moves downwardly and, as before stated, as the driver head moves upwardly, it leaves the roller 109 and permits the crank arm 96 to actuate the ejector bar 89 to project another rivet into the nest. The ejector bar 89 is held in its forward or its ejecting position whenever the driver head 58 is in an upper position, thus preventing a further feed of the rivets downwardly through the chutes. The foot treadle 74 is momentarily actuated to control the clutch, now shown, for a single revolution of the shaft 70 for each subsequent operation depends upon the movement of the treadle 74. The shaft 34 and the shaft 41 are coiitinuously actuated under the influence of the prime mover 38, functioning to continuously oscillate the shuttle plate 25 and to continuously actuate the kick-off wheel 40. The speed of the shaft 41 may obviously be varied by engaging the belt 45- upon either pair of pulleys 43 or 44.

Since the device has been adapted to handle rivets of varying size, it therefore becomes necessary at times to adjust the bars 47 apart to accommodate rivets having shank portions of different dimensions and also to adjust the bar 51 to accommodate the head portions of rivets of varying sizes. It is obvious, that with a single adjustment of the track bars, that a single size of rivet will be adapted thereto. In all other instances, the ejector mechanism and the rivet nest will remain in their fixed capacities and possibly the only other adjustment that may be found necessary is the adjusting of the shank 75 of the rivet holder to limit its traverse in either an upward or downward position. The shuttle plate 25 is continuously operating so long as the prime mover 38 is energized. To prevent the group of rivets in the hopper 21 from shifting over and on to the top of the trackway, there has been provided a baflie plate 21a that spans the hopper 21 to be frictionally held upon the side walls of the hopper and that terminates somewhat above the inclined bottom Such movement also covers the' 23, such bathe plate ila permitting a relatively large quantity of rivets to be disposed within the hopper andv fed to the trackway by the shut le 25 in a relatively small number with each stroke of the the plate 25. Mechanical elements such as conventional bearings, drive motors name like form no part of the present invention and it will be apparent that the several bearings will be in accordance with the function of the apparatus. It is contemplated that the continuous operation of the shuttle movement of the driver head to be projected into the rivet nest where they will be dislodged and forced downwardly into engagement with the workpiece, all of the functions being in the timed sequence calculated to actuate the mechanism in a predetermined cycle upon movement of the treadle 74. The movement of the rivets to the trackway is continuous and separate from the actuating mechanism for the driver head and the rivet holder.

It is to be understood that the invention is not limited to the precise construction shown, but that changes are contemplated as readily fall within the spirit of the invention as shall be determined by the scope of the subjoined claims. I

Having described our invention, what We claim as new and desire to secure by Letters Patent is:

l. A riveting machine of the character described having a main frame, a rivet hopper supported upon the frame, an inclined chute that communicates with the hopper whereby to receive and convey rivets by gravity downwardly to a discharge end of the chute, power driven means associated with the hopper for placing the rivets in a loading end of the chute, a rivet driving device supported by the frame and that is shiftable in a vertical path, power means for shifting the driving device, a rivet holder having an expandable rivet nest at its lower end, the rivet holder being yieldably and slidably connected to the driving device, the driving device when in an uppermost position functioning to dispose the rivet nest'adjacent to the discharge end of the chute, an ejector device that is movable in a path to eject 'a lowermost rivet in the chute into the rivet nest, crank means for shifting the ejector in a direction to discharge a rivet, the crank being biased in one direction by a' spring, means carried by the crank that lies in the path of movement of the rivet setting device whereby the crank is moved laterally upon the downward movement of the setting device to release the ejector, the downward movement of the driving device yieldably shifting the rivet holder and its rivet carrying nest to a point of engagement with a work piece that,

is disposed in overlying relation to an anvil, means for stopping the rivet holder in both an upper and lower position whereby to dispose the rivet nest in anjaccurate position with respect to the discharge end of the chute and the work piece, the movement of the driving device, the rivet holder and the ejector all being in a predetermined timed sequence and v actuatable by a single foot pedal, the said riveting setting device including a body portion and a lower reduced extension that terminates in a cylindrical punch that is in axial alignment with a rivet that is. supportedin the nest of the rivet holder, the body portion having at least one flat face, the rivet holder includingan elongated'body portion having at least one flat face that has sliding engagement with the flat face of the rivet setting body portion, the rivet setting body portion and the body portion of the rivet holder being slidable in a common housing, the fiat faces of the rivet setting device and rivet holder each having a mating groove, yieldable key means jointly engaging the grooves, a rocker arm journaled in a-frame extension and that has a linked connection with the upper end of the body portion, the rocker arm being intermittently actuated to im part a driving movement to the rivet setting device, the movement of the riveting setting device functioning to shift the rivet holder through the medium of the yieldable key means and adjustable stop means for limiting the upper and downward movement of the rivet holder.

2. A riveting machine of the character described having a main frame, a rivet hopper supported, upon the frame, an inclined chute that communicates with the hopper whereby to receive and conveyrivets by gravity downwardly to a discharge end of the chute, power driven means associated with the hopper for placing the rivets in a loading end of the chute, a rivet driving device supported by the frame and that is shiftable in a vertical path, power means for shifting the driving device, a rivet holder having an expandable rivet nest at its lower end, the rivet holder being yieldably andslidably connected to the driving device, the driving device when in an uppermost position functioning to dispose the rivet nest adjacent to the discharge end of the chute, an ejector device that is movable in a path to eject a lowermost rivet in the chute into the rivet nest, crank means for shifting the ejector in a direction to discharge a rivet, the crank being biased in one direction by a spring, mea ns carried by the crank that lies in the path of movement of'the rivet setting device whereby the crank is moved laterally upon the downward movement of the setting device to release the ejector, the downward movement of the driving device yieldably shifting the rivet holder and its rivet carrying nest to a point of engagement with "a Work piece that is disposed in overlying relation to an anvil, means forstopping the rivet holder in both an upper and lower position whereby to dispose the rivet nest in an accurate position with respect to the discharge end of the chute and the work piece, the movement of the driving device, the rivet holder and the ejector all being in a predetermined timed sequence and actuatable by a single foot pedal, the driving device and the rivet holder being movable in a vertical plane in a common guide housingpthe housing being supported upon the forward end of a frame extension, the said crank being hingedly connected to the guide frame at one end and with its lower end having contacting engagement with the ejector bar, a relatively heavy spring for biasing the crank arm in a direction to shift the ejector bar in a direction to eject a rivet into the rivet nest, a roller device carried by the crank arm and that extends through an open- 'ing in the guide housing to lie in the path of movement of the driving device whereby a downward movement of the drivingrdevice functions-to shift the crank arm to a position to release the ejector bar, driving means for the driving device that includes a rocker arm that is journaled intermediate its ends in the frame extension, a prime mover for driving the rocker arrn and with the prime mover drving a shaft, means carried by the shaft that has connection with one end of the rocker arm and foot controlled means for manually actuating a clutch between the prime mover and the shaft whereby the shaft will make one complete revolution. I

3. The structure according to claim' 1 wherein the key means include a pair of plugs that are biased apart by a compression spring.

4. In a riveting machine, a rivet driving device and a rivet holder movable in a vertical plane through a guide housing, driving imeans coupled to the drving device for vertically reciprocating it, the driving device being provided with an elongated, groove, the rivet holder being provided with a similar groove facing the groove in the driving device, members complementary to and fitting into the both grooves and permitting relative sliding movement between the driving device and the setting device, and a spring fitted in the grooves and disposed 9 10 between the members and tending to urge said members 2,310,008 Wolfi Feb. 2, 1943 apart. 2,652,942 Muchy Sept. 22, 1953 2,829,387 Carangelo Apr. 8, 1958 References Clted 1n the file of 1111s patent 2,832,971 Tesch May 6, 1958 UNITED STATES PATENTS 5 1,596,366 Miller Aug. 17, 1926 FOREIGN PATENTS 1,850,671 Havener Mar. 22, 1932 37 ,360 Great Britain May 6, 1932 

